Various proposals have been made heretofore for providing a furnace and the like high temperature chambers with an insulative lining avoiding the disadvantages of rigid refractory material such as bricks and cast components. Such proposals involve the use of refractory fibers formed into mats, slabs, blankets and other configurations. The refractory or ceramic fibers are customarily laid down in randomly arranged layers interbonded to one another at points of crossover. Typically, chambers insulated with refractory fibers operate in a temperature range of 1,600 degrees to 2,800 degrees F. a satisfactory insulation assembly utilizing refractory fibers requires an insulation thickness of four to six inches or more. Blankets of such fibers are applied with the layers lying generally parallel to the chamber wall, serious problems are encountered including those of securing the blankets to the wall and particularly the problem of delamination and spalling or peeling off of successive surface layers resulting in a relatively short service life. To avoid these problems and others associated therewith it has been the practice to utilize a wide variety of arrangements in which the fiber blankets, one to two inches thick are secured to the chamber wall with the fiber layers lying in planes generally normal to the chamber wall. This avoids the serious delamination and spalling problems but presents other problems associated with the assembly of liner modules or components formed of multiple layers held assembled in side-by-side relation and provided with suitable heat resistant means for securing the assembly to the chamber wall. Another problem present in modules formed of layers of fibers held compressed against one another adjacent the outer or cold face of the module results in the inner or hot face being unrestrained and free to flare away from one another. This flaring tendency of the unrestrained layers is highly desirable when the modules are installed closely adjacent one another but can handicap the installation operation because interfering with the workman's access to fasteners securing the module to the chamber wall. Additionally the flaring edges of the end layers present packaging and stowage problems prior to installation and these unprotected edges are exposed to handling damage.
Patents in this art dealing with these problems and proposing a variety of solutions include: Sauder et al U.S. Pat. No. 3,819,468; Ballaz et al U.S. Pat. No. 3,832,815; Brady U.S. Pat. No. 3,854,262; Monaghan U.S. Pat. No. 3,892,396; Sauder et al U.S. Pat. No. 3,940,244; Byrd U.S. Pat. No. 3,952,470; Byrd U.S. Pat. No. 4,001,996; Byrd U.S. Pat. No. 4,012,877; Byrd U.S. Pat. No. 4,103,469; Myles U.S. Pat. No. 4,120,641; Byrd U.S. Pat. No. 4,123,886; Cunningham et al U.S. Pat. No. 4,218,962; Severin et al U.S. Pat. No. 4,287,839; Hounsel et al U.S. Pat. No. 4,381,639; European Patents Publication No. 0,018,677 and U.K. patent application No. 2,004,626 A.
The two Sauder patents propose a complex module assembly formed of a multiplicity of individual strips of refractory fiber mounted along one edge to an expanded metal backing or held assembled to a backing layer of fibers by means of a complex series of tie wires criss-crossing one another. The several Byrd patents show different techniques for folding a ceramic blanket with certain folds embracing an elongated anchor member provided with tang means protruding outwardly through the folds with the outer end clenched to an elongated mounted strip securable to a furnace wall.
The Cunningham and Hounsel patents show closely related variants of the several Byrd teachings. Bolus and Brady both propose modules composed of separate strips of refractory fibers required to be assembled individually in side-by-side relation and held assembled by a plurality of pins on which all strips are impaled and secured to retain members at the opposite ends of the pins. Brady's clamping pins are staggered relative to one another and the retaining members are secured to a mounting plate coextensive with the outer edges of the strips and securable to a furnace chamber, whereas Balaz extends his pins through eye bolts utilized to clamp the module to the chamber wall. Monaghan secures one end of L-shaped mounting hooks to the chamber wall and having a pointed leg extending upwardly and spaced from the wall. Individual strips of insulating fibers are then impaled over the upright legs. Miles places a multiplicity of ceramic fiber strips in side-by-side relation and bonds one lateral edge to an expanded metal mounting strip. The module is then secured to the wall by round ended buttons forcibly inserted into respective expanded metal openings.
Severin et al, proposes a pleated ceramic fiber blanket utilizing a multiplicity of components including a channel shaped baseplate, a pair of rods piercing all pleats and having their ends anchored in tabs secured to a base plate provided at its corners with J-shaped suspension bolts engageable with pairs of rods mounted on the interior of a furnace wall. The European publication extends ceramic tubes through adjacent layers of refractory fibers. These tubes also pierce one end of suspension ceramic tubes having their other ends projecting beyond the cold edges of the layers and serving to seat hook members engageable with the structural elements of the chamber wall. The outermost edges of the layers are also bonded to one face of large ceramic baseplate. Modules formed by this technique are sufficiently large to extend across the width of a furnace wall.